Insulin and C-peptide responses to glucose load in cystic fibrosis.

Immunoreactive Insulin and C-peptide responses to glucose load were estimated in patients with cystic fibrosis and in controls. Both insulin and C-peptide responses were low in cystic fibrosis patients and the changes were more marked in those with glucose intolerance. There appears to be true pancreatic hyposecretion of insulin in patients with cystic fibrosis whereas the peripheral sensitivity of insulin seems to be normal or enhanced.